The Man John L. Sullivan Feared William Muldoon reigned as undefeated World Heavyweight Wrestling Champion for 9 years before embarking on a career as America's first celebrity trainer. Initially training athletes like John L. Sullivan, Muldoon trained athletes, businessmen and politicians at the first health resorts in America. Read about the Solid Man vanquishing his foes in the ring and meeting challenges outside of it. The Last American World Champion Who Wrestled Greco-Roman Style